Communication terminal apparatus, base station apparatus and communication system

Abstract

A communication system includes a communication terminal, base stations performing radio communication with the communication terminal, and a host device of the base stations. A serving base station of the communication terminal or the host device selects, from among the base stations, a positioning base station transmitting a positioning signal for measuring a position of the communication terminal. The positioning base station transmits the positioning signal, and the communication terminal receives the positioning signal. The communication terminal, the serving base station, or the host device estimates the position of the communication terminal, based on a reception result of the positioning signal from the communication terminal, and a specific-precision positioning base station that can communicate with the communication terminal via direct waves is selected as the positioning base station when positioning precision required for positioning of the communication terminal is higher than or equal to specific precision (ST 1450 , ST 1452 , ST 1453 ).

1 . A communication terminal apparatus in a communication system, the communication system comprising: the communication terminal apparatus; and a base station apparatus including a Transmission Reception Point (TRP) configured to communicate with the communication terminal apparatus,
 wherein the communication terminal apparatus is configured to transmit a positioning signal for estimating a position of the communication terminal apparatus to the TRP.   
     
     
         2 . The communication terminal apparatus according to  claim 1 , wherein the positioning signal is a Sounding Reference Signal (SRS) for positioning. 
     
     
         3 . The communication terminal apparatus according to  claim 1 , wherein the communication terminal apparatus is configured to receive information on the positioning signal from the base station apparatus. 
     
     
         4 . The communication terminal apparatus according to  claim 3 , wherein the information on the positioning signal includes information on a time resource and a frequency resource for the positioning signal. 
     
     
         5 . The communication terminal apparatus according to  claim 4 , wherein the information on the positioning signal further includes information on a code sequence of the positioning signal. 
     
     
         6 . The communication terminal apparatus according to  claim 1 , wherein the communication terminal apparatus is configured to receive information on a position of the TRP from the base station apparatus. 
     
     
         7 . The communication terminal apparatus according to  claim 6 , wherein the information on the position of the TRP is included in a System Information Block (SIB). 
     
     
         8 . The communication terminal apparatus according to  claim 1 , wherein the base station apparatus is configured to transmit information on the positioning signal to another base station apparatus. 
     
     
         9 . The communication terminal apparatus according to  claim 1 , wherein the communication system further comprises a Location Management Function (LMF) apparatus, and
 the LMF apparatus is configured to transmit information on the positioning signal to the base station apparatus.   
     
     
         10 . The communication terminal apparatus according to  claim 9 , wherein the information on the positioning signal includes information on a time resource and a frequency resource for the positioning signal. 
     
     
         11 . The communication terminal apparatus according to  claim 10 , wherein the information on the positioning signal further includes information on a code sequence of the positioning signal. 
     
     
         12 . The communication terminal apparatus according to  claim 9 , wherein the LMF apparatus is configured to further transmit information on a beam to the base station apparatus. 
     
     
         13 . The communication terminal apparatus according to  claim 9 , wherein the LMF apparatus is configured to further transmit information on the TRP to the base station apparatus. 
     
     
         14 . The communication terminal apparatus according to  claim 1 , wherein the communication system further comprises a Location Management Function (LMF) apparatus, and
 the base station apparatus is configured to transmit information on a position of the TRP to the LMF apparatus in response to a request from the LMF apparatus.   
     
     
         15 . A base station apparatus in a communication system, the communication system comprising: a communication terminal apparatus; and the base station apparatus including a Transmission Reception Point (TRP) configured to communicate with the communication terminal apparatus,
 wherein the TRP is configured to receive, from the communication terminal apparatus, a positioning signal for estimating a position of the communication terminal apparatus.   
     
     
         16 . A communication system comprising: a communication terminal apparatus; and a base station apparatus including a Transmission Reception Point (TRP) configured to communicate with the communication terminal apparatus,
 wherein the communication terminal apparatus is configured to transmit a positioning signal for estimating a position of the communication terminal apparatus to the TRP.